Comparison of sodium citrate with defibrination for the processing of blood for tsetse mass-rearing

Full text: Various experimental bioassays comparing the use of sodium citrated bovine blood to defibrinated bovine blood were performed in order to reach an alternative anticoagulant procedure. Defibrination is the standard process to obtain blood, which is the only source of nutrients for tsetse flies. This process is time consuming, requires special equipment, trained personnel and could be an extra source of blood contamination. For the blood collection, special care was taken to rule out biological bias by using the same donor animal for both citrated and defibrinated collections. Contamination was avoided by sterile collection from the jugular vein. As the university owns these animals, their medical history is known and could be inspected prior to collection in order to rule out any recent antibiotic treatments, which could influence the results of the experiment. Both blood treatments were transported under refrigeration, irradiated in a Gammacell 220 Co60 irradiator with 1 kGy, stored at -20 deg. C and bacteriologically tested (nutrient agar plate test). All flies were kept under standard condition of temperature (24.5 ± 0.5 deg. C) and relative humidity (75 ± 5%). For the bioassays, flies from the Glossina pallidipes colony, Entomology Unit, Seibersdorf, were used. The flies were divided into 2 groups of males and females in a 1:4 ratio and each group was composed of 4 cages. The first experiment lasted for 37 days and the second 93 days. One group received defibrinated bovine blood and the other group received citrated bovine blood (0.02M final concentration). Survival, mortality and fecundity rates of the flies and pupal size category and weight were recorded for both groups and were analysed and compared. The results showed that there was no significant difference between the two treatments for survival, mortality and fecundity and that the pupal size category and weight for the citrated group had slightly better results than the defibrinated group. The use of citrate as an anticoagulant for the large-scale collection of blood was also tested in trials at 2 different slaughterhouses. A sodium citrate toxicity test was also conducted which indicated that tsetse flies could tolerate citrate concentrations up to 0.04M. (author)